The present invention relates to flywheel and transmission assemblies for vehicles, and in particular, to such an assembly which includes an adaptor disposed between the flywheel housing and the transmission clutch housing.
Although the present invention may be used advantageously in practically any vehicle application, it is especially suited for use with a flywheel and transmission assembly for a truck, and especially for a heavy duty truck, and will be described in connection therewith.
As is well known to those skilled in the art, many of the drive train components, as well as other components, of heavy duty trucks, are specified by the ultimate vehicle owner, such as the owner or operator of a fleet of trucks. Partially as a result of such a component selection process, a particular truck may ultimately be equipped with any one of a number of different transmission-and-clutch combinations, and either of several different engine and flywheel combinations.
It is necessary to mate or match the flywheel housing and the transmission clutch housing, typically, bolting the latter to the former. Among the commonly used flywheel housings, some are provided with a series of bolt holes which comprise an SAE No. 1 pattern, while others are provided with a series of bolt holes which comprise an SAE No. 2 pattern.
As a result, it has generally been necessary, for any given transmission, to tool and manufacture at least two different transmission clutch housings, one having an SAE No. 1 bolt pattern and another having an SAE No. 2 bolt pattern, with the appropriate transmission clutch housing being assembled to the transmission for assembly in the vehicle. The need to tool and manufacture two different transmission clutch housings, to be able to mate with either of two different flywheel housings, adds substantially to the manufacturing and inventory costs of such transmissions.
In an attempt to overcome the problem described above, some of those skilled in the art have attempted to provide an adaptor between the transmission clutch housing and the flywheel housing which would facilitate the use of a transmission clutch housing having an SAE No. 2 bolt pattern with a flywheel housing having an SAE No. 1 bolt pattern. However, the typical adaptor which has been provided has changed the relative axial location between the flywheel and the transmission, thus necessitating a change in the input shaft configuration, i.e., typically the length of the input shaft.